sql求救

Question

原始表（字段都是数据类型的）
 A B   c
2012 1   20
2012 2   0
2012 3   50
2012 4   0
2012 5   0
2012 6   0
2012 7   0
2012 8   80
2012 9   0
2012 10   0
2012 11   90
2012 12   0有没有可能使用sql语句是变成这样的结果（最好以试图的形式出现）
 A B   c
2012 1   20
2012 2   20
2012 3   50
2012 4   50
2012 5   50
2012 6   50
2012 7   50
2012 8   80
2012 9   80
2012 10   80
2012 11   90
2012 12   90不能用存储过程

Answer 1

额，自己搞定 
select b.a,b.b,case when c<>0 then c else (select sum(c) from view_tst_aaa a where  a.b<=b.b and a.b>=(select max(c.b) from view_tst_aaa c where c.c>0 and c.b<=b.b)) end 
from view_tst_aaa b

Answer 2

create table T
(
  A VARCHAR2(4),
  B INTEGER,
  C INTEGER
)
;
insert into T (A, B, C)
values ('2012', 1, 20);
insert into T (A, B, C)
values ('2012', 2, 0);
insert into T (A, B, C)
values ('2012', 3, 50);
insert into T (A, B, C)
values ('2012', 4, 0);
insert into T (A, B, C)
values ('2012', 5, 0);
insert into T (A, B, C)
values ('2012', 6, 0);
insert into T (A, B, C)
values ('2012', 7, 0);
insert into T (A, B, C)
values ('2012', 8, 80);
insert into T (A, B, C)
values ('2012', 9, 0);
insert into T (A, B, C)
values ('2012', 10, 0);
insert into T (A, B, C)
values ('2012', 11, 90);
insert into T (A, B, C)
values ('2012', 12, 0);
commit;select t.a,t.b,t1.c
  from t,
       (select a, b, lead(b, 1) over(order by a, b) r, c from t where c <> 0) t1
 where t.b >= t1.b
   and (t.b < t1.r or t1.r is null)A                                          B                                       C
---- --------------------------------------- ---------------------------------------
2012                                       1                                      20
2012                                       2                                      20
2012                                       3                                      50
2012                                       4                                      50
2012                                       5                                      50
2012                                       6                                      50
2012                                       7                                      50
2012                                       8                                      80
2012                                       9                                      80
2012                                      10                                      80
2012                                      11                                      90
2012                                      12                                      90
 
12 rows selected

Answer 3

select a,b,(select max(c) from tab t1 where t1.a = t.a and to_number(t1.b) >=to_number(t.b))
from tab t

Answer 4

SELECT t.*,
       nvl(last_value(nullif(c, 0) ignore NULLS) over(ORDER BY b), 0) a1
  FROM t;
A                                          B                                       C         A1
---- --------------------------------------- --------------------------------------- ----------
2012                                       1                                      20         20
2012                                       2                                       0         20
2012                                       3                                      50         50
2012                                       4                                       0         50
2012                                       5                                       0         50
2012                                       6                                       0         50
2012                                       7                                       0         50
2012                                       8                                      80         80
2012                                       9                                       0         80
2012                                      10                                       0         80
2012                                      11                                      90         90
2012                                      12                                       0         90
 
12 rows selected
 
今天看到一个更简单的方法